Transcript divisibility rules

DIVISIBILITY RULES
LESSON 1
Dividing by 2
All even numbers are divisible by 2.
Any number that ends in 0,2,4,6, or
8.
32 - ends with a 2 therefore an even number
157 - ends with a 7 therefore not an even number
Add up all the digits in the number.
Find out what the sum is.
If the sum is divisible by 3, so is the number
If the sum of the digits of a number
add up to a number that can be
divided by 3, then so can that
number.
36 : adds up to 9 therefore 36 can be divided by 3.
157 - adds up to 13 therefore 157 can not be divided by 3
Are the last two digits in your number divisible by 4?
If so, the number is too!
If you can divide the last two digits
in a number by 4, then the bigger
number can also be divided by 4.
136 : 36 can be divided by 4 therefore 136 can be
divided by 4.
157 : 57 can not be divided by 4 therefore 157 can not be
divided by 4
Numbers ending in a 5 or a 0 are always divisible by 5
If the last digit of a number is 5 or
zero (0) then the number can be
divided by 5.
135 : ends in a 5 therefore 135 can be divided by 5.
157 : ends in a 7 therefore 157 can not be divided by 5
If the Number is divisible by 2 and 3 it is divisible by 6 also.
If the number is even and adds up
to a number that you can divide by
3 then it can be divided by 6.
144 : ends in a 4 and adds up to 9 therefore 144 can
be divided by 6.
154 : ends in a 4 but adds up to 10 therefore 154 can not
be divided by 6. because you can’t divided it by 3.
This one's not as easy:
If the last 3 digits are divisible by 8, so is the entire number.
You look at the last three numbers
of a big number and see if they can
be divided by 8.
1568 : Since 568 can be divided by 8, so can 1568.
2564 : Since 564 can not be divided by 8, neither can 2568.
Almost the same rule and dividing by 3.
Add up all the digits in the number.
Find out what the sum is. If the sum is divisible by 9, so is
the number.
If the sum of the digits of a number
add up to a number that can be
divided by 9, then so can that
number.
369 : adds up to 18 therefore can be divided by 9
2564 : adds up to 17 therefore can not be divided by 9.
If the number ends in a 0, it is divisible by 10.
If the last digit of a number is or
zero (0) then the number can be
divided by 10.
360 : ends in 0 therefore can be divided by 10
2564 : ends in 4 therefore can not be divided by 10.
TRY THESE
 LIST
WHETHER THE FOLLOWING
NUMBERS ARE DIVISIBLE BY:
2,3,4,5,6,8,9,10
 1) 456
 2) 3298
 3) 56 784
 4) 2960
TRY THESE
 LIST
WHETHER THE FOLLOWING
NUMBERS ARE DIVISIBLE BY:
2,3,4,5,6,8,9,10
 1) 456
= {2,3,4,6,8}
 2) 3298
 3) 56 784
 4) 2960
TRY THESE
 LIST
WHETHER THE FOLLOWING
NUMBERS ARE DIVISIBLE BY:
2,3,4,5,6,8,9,10
 1) 456
= {2,3,4,6,8}
 2) 3298
= {2}
 3) 56 784
 4) 2960
TRY THESE
 LIST
WHETHER THE FOLLOWING
NUMBERS ARE DIVISIBLE BY:
2,3,4,5,6,8,9,10
 1) 456
= {2,3,4,6,8}
 2) 3298
= {2}
 3) 56 784 = {2,3,4,6,8}
 4) 2960
TRY THESE
 LIST
WHETHER THE FOLLOWING
NUMBERS ARE DIVISIBLE BY:
2,3,4,5,6,8,9,10
 1) 456
= {2,3,4,6,8}
 2) 3298
= {2}
 3) 56 784 = {2,3,4,6}
 4) 2960
= {2,4,5,8,10}
HOMEWORK
 Divisibility
Rules Handout